As many of you know, modern color copiers/Photoshop/some cameras detect currency and refuse to scan/open/photograph these images. There has been some work in reverse-engineering what algorithms are used to determine what is currency. However, I've yet to see anything conclusive. I am very much interested in expanding this work towards the end of creating false positives. Think like a T-shirt that when worn would make you difficult to photograph, or artists/journalists being able to embed currency watermarks inside photos that they dont want people to photoshop, or being able to watermark secret documents so they cannot be copied, etc.
Off side interests, it has been discovered that in particular HP Printers & Scanners, as well as Paint Shop Pro/Paint Shop Pro all do have anti-counterfeiting mechanisms. However, the schemes they implement seem to be very different.
Consider this a call for any comments/knowledge related to this issue with particular interest in Photoshop/Paint Shop Pro's currency detection.